Using Plane as Object transform "final" output
If you want the grid of cubes to follow the angle of the faces of the plane, you can use the plane itself to define the grid locations and angles.

In this example, I created a plane, subdivided it into 32 polygons (4x8), then applied the Simple Deform modifier to the plane to create a curve.

In Animation Nodes, you can use the Object Mesh Data node to get the locations of the polygons making up the plane, as well as the normal angles of their faces.

Then, just instance the cubes at the locations of the polygon centers, and apply the angle of rotation using the face normal.

I also used the normal angle to constrain the wiggle, so the cube moves perpendicular to the face of the curve.



I created this in Blender 2.79 / AN 2.0.4, but equivalent nodes are available in later versions of AN and Blender as well.